Creach was a Vampire and a former member of Dracula's family before being 'recruited' by the Joker.
Biography[]
His life prior to his appearance in Gotham is unknown, but it would appear that Creach spent a long time crawling out of his grave after he was turned into a vampire, which somehow resulted in his stomach and intestines being exposed when he is in human form. When most of Dracula's vampires were lured into a trap by Tanya and her Others, Creach and a small group escaped this fate for unknown reasons, and were unable to reunite with Dracula before Batman destroyed their master the following night.
Bloodstorm[]
Following the death of Dracula and the destruction of most of his family, Creach and the few surviving vampires remained hidden in Gotham's sewers, occasionally coming out to attack the city's homeless, but unable to grow any further as the now-vampire Batman always found and staked their victims before they could rise.

Creach and the Joker
Eventually, the vampires were discovered by the Joker, who used a squirting lapel filled with holy water and a crucifix to drive the vampires back while he pointed out the absurdity of them attacking him given their current inability to think beyond their next meal with Dracula's defeat. Impressed by his nerve and acknowledging his point about their short-term actions, the vampires agree to let the Joker lead them as a human so long as his leadership produces results, with Creach being appointed the Joker's 'right-fang-man' for his nerve in threatening to use a brick to disarm the Joker of his crucifix.
During a solo hunt, Creach attempted to feed on local woman Selina Kyle, eventually chasing her down while he assumed the form of a wolf, but she was able to escape after he bit her shoulder by kicking him and diving off a bridge, Creach being unable to cross running water.
Although the Joker successfully coordinates the vampires' efforts to turn and take control of all of Gotham's major crime families- intending to expand from there to turn the rest of Gotham, and then the rest of the country-, Batman and Selina- transformed into a were-cat by Creach's bite and determined to destroy the monster that did this to her- were able to destroy the Joker's minions, tracking down their new nests and then contacting Batman's daylight allies Commissioner Gordon and Alfred Pennyworth to eliminate the turned mobsters while they slept.

Creach's death
Leading the last of his vampires- numbering only fifteen- into a warehouse, the Joker attempted to capture Batman and Selina in an ambush, but the plan resulted in the deaths of all his minions. Creach attempted to escape by turning into a wolf, but Selina, recognizing him as her attacker, subsequently tore him to pieces, ripping his heart out of his chest.
Powers and Abilities[]

Creach as a wolf
Like other vampires of Earth-43, Creach possessed superhuman strength, speed, and stamina, as well as an immunity to most injuries apart from decapitation and a stake through the heart (Although later evidence revealed that the stake merely immobilisies unless decapitation takes place as well). He was also vulnerable to sunlight. Creach was shown to be capable of turning into a wolf, and his words implied that he could also become a bat if he wished, suggesting that he was a particularly powerful vampire as only Dracula and Batman were shown to be capable of shapeshifting aside from him.